Nonlinear Optical Parametric Process Pumped By Incoherent Light

This paper deals with the nonlinear parametric process of temporal incoherent light in the optical waveguide, including the Four-wave mixing process in the third-order nonlinear medium (nonlinear optical fiber) and three-wave parametric process in the second-order nonlinear medium (such as Ti: LiNbO₃).Particularly, the four-wave mixing (FWM) process between a coherent signal light and an incoherent pump light in a highly-nonlinear fiber is studied experimentally and theoretically. It shows that the incoherent pump would lower the coherence of the signal light.In addition, the spontaneous generation of coherent light in co-propagating FWM process occurred in photonic crystal fiber is theoretically studied. The analysis shows that this phenomenon requires the same group velocities of pump and idler light, as well as the convection (walk off) between the signal and pump/idler waves.Similarly, the backward parametric oscillation pumped by incoherent light in the second-order nonlinear crystal waveguide is investigated. It indicates that because of the extremely large convection between the signal and pump/idler, the backward parametric oscillation process is very promising to realize the spontaneous generation of coherent light from incoherent pump light.